Step 1

The night before you want to roast your lamb, cut 1 inch slits in the leg of lamb. Stuff the slits with garlic slices and rosemary sprigs. Place the lamb in a roasting pan with a roasting rack. Cover lightly with plastic wrap and refrigerate overnight to infuse with flavor.

Step 2

Remove the lamb from the refrigerator 2-3 hours before you want to start cooking to let it come to room temperature.

Step 3

Preheat your oven to 450F.

Step 4

Drizzle the lamb with olive oil and sprinkle with salt and pepper. If you have an in-oven probe thermometer, insert it into the center of the meatiest part of the leg.

Step 5

Roast the lamb at 450F for 15 minutes.

Step 6

Reduce your oven temperature to 300F. Open the oven door slightly to help drop the heat more quickly.

Step 7

Continue to roast the lamb at 300F for 20-25 minutes per pound for medium rare (or 25-30 minutes a pound for medium). (For a 5-6 lb leg of lamb, this means you will be roasting 1.5-2.5 hours for medium rare or 2-3 hours for medium.)

Step 8

Remove the lamb from the oven when it has reached 135F internal temperature for medium rare (or 150F for medium).

Step 9

Rest the lamb on the counter for 10-15 minutes, tented loosely with aluminum foil. As it rests, it will continue to cook. Your ending temperature for medium rare should be 145F (or 160F for medium).

Step 10

Carve the leg (as instructed in our article) and serve with green beans and gratin potatoes!